Frédéric Bastiat

If Exchange saves efforts, it also exacts them. It extends, and spreads, and increases, up to the point at which the effort it exacts becomes equal to the effort which it saves, and it stops there until, by the improvement of the commercial apparatus, or by the circumstance exclusively of the condensation of population, and bringing men together in masses, it again returns to the conditions which are essential to its onward and ascending march. Whence it follows that laws which limit or hamper Exchanges are always either hurtful or superfluous.
Governments which persuade themselves that nothing good can be done but through their instrumentality, refuse to acknowledge this harmonic law.
Exchange develops itself NATURALLY until it becomes more onerous than useful, and at that point it NATURALLY stops.
In consequence, we find governments everywhere busying themselves in favouring or restraining trade.
In order to carry it beyond its natural limits, they set to conquering colonies and opening new markets. In order to confine it within its natural bounds, they invent all sorts of restrictions and fetters.

Frédéric Bastiat, Harmonies of Political Economy (from the Third French Edition, Patrick James Stirling, trans.).